Mechanical Iris V2.0




About: Teacher of Science and engineer

Before anything else, I would like to say that this Instructable is based on and inspired by carlbass and his Mechanical iris.


Inspired by his work I quickly put a piece of plywood in my desktop laser cutter and set it to work. Minutes later the promise appeared, and within moments I had pieced everything together in a fully functioning mechanical iris. Awesome!

However, after admiring the design I spotted few ways in which I felt it could be improved.

So here it is; my take on the Mechanical iris (v2.0).

Step 1: Improvements

- In the original Mechanical iris there were three layers. I felt this was excessive and so this new design offers only two (plus 1mm for the optional Perspex cover).

- The points at which the 'arms' attached to the blades relied on a shared pin to partially rotate about. This aspect seemed over complicated when the same effect could be achieved with clever cutting. This means that post cutting assembly time is reduced.

- The holes have been changed to fit 6mm dowel instead of 5mm which, for some reason I found stupidly difficult to obtain.

- Drawing pins have been used to cap the wooden dowel pins ensuring that the blades and outer ring do not wonder or come off. This design does not however ensure the arms are kept in place when holding the finished product upside down. This is where the optional 1mm Perspex cover comes in should you feel you need it.

- Although this last part is very crude in its current design, I have included a use for the offcuts. Stuck together they form a raised grip for the back of the iris enabling you to hold and manipulate it more easily. This will prove its worth when you come to 'working' the outer ring in for a couple of minutes.

Step 2: Materials

Wood glue
Drawing pins
Your choice in wood
6mm dowel
Scalpel / hobby knife

1mm colourless Perspex (optional)

Step 3: Laser Cutting Files

Below are a choice of files for you to use. I couldn't think of any other file type you might need, so if I'm missing a major one please message me and I'll see if I can sort something out.

P.s. The .dxf and .svg files are a slightly updated version -- there are two turning handles so the iris can be used in one hand now.

Step 4: Assembly

Assembly is very easy.

  1. Measure and cut a 6mm long length of your dowel.
  2. Use your knife to press down and cut as you roll the dowel back and forth.
  3. Repeat steps 1 and 2 a further nine times.
  4. Dab a small amount of glue in one of the base layer holes.
  5. Take one of the dowel 'lugs' and rotate/push into the glued hole.
  6. Ensure that the lug is flush with the back of your base layer.
  7. Wipe away any excess glue.
  8. Repeat steps 4-7 for the remaining 9 lugs.
  9. Glue the two semi circle off-cuts together and then glue to the back of the iris where you feel is most comfortable.
  10. Wait for the glue to dry.
  11. Place the outer ring over the glued lugs then spend a few minutes carefully working it in by repeatedly rotating it. You may need to shave minute amounts off the inside and outside of the lugs.
  12. Once the outer ring turns with minimal force add the blades and the arms linking everything up as you go.
  13. OPTIONAL - If you want to use a Perspex cover, this is where you would lay it over the top making sure that all holes align with the lugs underneath.
  14. Carefully push a drawing pin into the centre of each lug ensuring that the top of the drawing pin does not exert too much pressure on the piece reducing its mobility. Remember, these are merely a way of stopping the pieces falling off -- I left a fingernail's spacing under each one.

Step 5: Finished Product

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37 Discussions


1 year ago



1 year ago

love it!


1 year ago

How did you deal with the .dwg being drawn completely using splines? It seems like that would make it much more difficult to manipulate :-/


Reply 2 years ago

Really doesn't matter that much. I used 3mm, but I suppose anything up to 6mm would work without looking too chunky.


2 years ago

hi, can you please send me the files by email? i dont want to buy membership on email is i really need this for a school project

1 reply

Reply 2 years ago

No need to buy a membership, the files are there.


3 years ago

Clever design with the non-use of pins. Any chance you've made one with 8 blades? I've been scouring the web to find the calculations needed in designing this but have come up with none.Thanks!


3 years ago

thanks a million.


Reply 4 years ago

I'll stick one up this weekend. Of course if you can't wait that long you could always convert one of the existing formats to .svg


I'm thinking of ways to change the design to make the border (which contains all of the mechanics) around the hole as small as possible. If this would be the frontdoor to a house, and the diameter of the hole is 2 meters (6.56 feet), the ring would extend two meters around that, including into the ground. There has to be a way to minimise this.

3 replies

Reply 5 years ago on Introduction

You're absolutely right. This design is limited because it does not overlap. As a result and as can be seen, everything must be spread out around the centre. To get past this you should be looking at an over-lapping iris. Something like this:

This one works well because the mechanism isn't restricted to one layer (the blades are also very thin by comparison). This would work best in thin metal and with a lot of oil.

Hope that's food for thought. And thank you for the compliment btw.


Reply 4 years ago on Introduction

This sounds like it can work. I want to make it as a door to a 1 1/2 foot opening. Any ideas/help/suggestions would be awesome!! I have access to a laser cutter.


Reply 5 years ago on Introduction

Personally, I don't like the overlapping designs because they never
seem to fully close, whereas a large version of this one could be built
with tongue and grooves between the blades for a very solid closure.

Adding more blades should make the blades smaller, to lessen the width of the border. That said, I'm stuck on the math of how to make this happen beyond the 5 here. Maybe more blades could be worked out with compass and a lot of paper, but I'm not 100% sure it'll work.

That said, if you aren't minimizing the layers, and you keep 5 blades, you'd only need 1x the blade width outside of the doorway, so about 1 meter (Where the corners stop at 'open'). The actuation ring could be where the corners stop, such that the swing arms are tangent to the circle. It adds 2 layers to this design, but removes that 1m extra 'depth' around the door for you.


4 years ago

Hi! For any reason I don't see the dxf and the svg files. Would you please make it available for me? I am very excited of trying to reproduce your project.


5 years ago on Introduction

Great piece. I've been playing with it to use flexing arms from the outer ring to the petals, and having no moving joints except the outer ring.

2 replies

Reply 5 years ago

That's an interesting idea. I'd like to see some pictures of that


Reply 5 years ago on Introduction

I'm Struggling with materials....thin laser ply is useless.....I might try PET-G